| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical element can reduce a phase difference between two polarized light rays to exhibit excellent optical characteristics even if light rays are incident at an incident angle of 55° or more. <P>SOLUTION: The optical element is used for light with wavelength of 250 nm or less, and the maximum incident angle of a light ray incident on the optical element is 55° or more. The optical element has an optical thin film in its light ray effective area, and in the film thickness distribution of the light ray effective area, a film thickness of the optical thin film in the outermost circumference of the light ray effective area is 1.10-1.25 times that of a midpoint between an optical axis and the outermost circumference of the light ray effective area. <P>COPYRIGHT: (C)2009,JPO&INPIT |
